This cake is out of this world! :DDDDDDD
omnomonmonmonmonm
...
something else is out of place too.
Note: This is not a steganography challenge
Decompress the pdf using qpdf:
qpdf --qdf prettydeliciouscakes.pdf temp.pdf
In the decompressed pdf:
const data = 'c3Vue3AzM3BfZDFzX2ZsQGdfeTAhfQ==';
Decode the base64 to get flag: sun{p33p_d1s_fl@g_y0!}.